60 years after U.S.’s first satellite success, space program thriving

At 22:47:56 EST on Friday, 31 January 1958 (03:47 UTC on 1 February), a Juno I rocket lifted off from Cape Canaveral’s Launch Complex 26A and successfully placed the Explorer 1 satellite into orbit around the Earth. The launch made the United States the second country to place a satellite into orbit – four months after the Soviet Union orbited Sputnik 1. Sixty years laters, the state of the US launch industry is strong thanks in large part to the proliferation of new commercial entrants into a long-standing market.

In 1955, the United States had committed itself to placing a satellite into orbit during the International Geophysical Year, which ran from 1 July 1957 to 31 December 1958. The Naval Research Laboratory’s Vanguard rocket had been chosen to perform the launch as it was derived from Viking, a sounding rocket, as opposed to a missile.

A Vanguard rocket fails on the launch pad shortly after liftoff on the US’s first attempt to place a satellite into orbit on 6 December 1957. Credit: NASA

After Vanguard’s failure, the US turned to the Army Ballistic Missile Agency (ABMA), an agency within the US Army dedicated to missile development, and Explorer 1 was eventually launched by the ABMA in conjunction with the Jet Propulsion Laboratory (JPL).

The Juno I rocket that carried Explorer 1 into orbit was a four-stage version of the Jupiter-C test vehicle, which was itself derived from the PGM-11 Redstone missile. The Redstone was an early nuclear-capable short-range ballistic missile (SRBM) and was a development of the V-2 rocket which had been employed by Nazi Germany during the Second World War.

At the end of the war, many of Germany’s leading rocket scientists, including Wernher von Braun, the V-2’s principal designer, and his team surrendered to the United States. Under Operation Paperclip, these scientists were brought to the US to help advance the nation’s military technology against the backdrop of the Cold War.

For the Explorer 1 launch, Jupiter-C incorporated a stretched Redstone as its first stage, with its second and third stages consisting of clustered solid rocket motors derived from the MGM-29 Sergeant missile.

The Explorer 1 satellite itself was actually built around a Sergeant rocket motor, which served as the Juno I’s fourth stage. The cylindrical satellite had a mass of 13.97 kilograms (30.80 lb) and measured 203 centimetres (79.9 inches) in length and 15.2 centimetres (5.98 inches) in diameter.

After launch was completed, Explorer 1 was found to be in a 358-by-2,550-kilometre (222 x 1,584 mile, 193 x 1377 nautical mile) orbit, inclined 33.24 degrees to the equator, in which it completed one revolution of the Earth every 114.8 minutes. The spacecraft remained in orbit until 31 March 1970.

Unlike its two Sputnik predecessors, Explorer 1 was the first satellite to research the space environment via instruments, which included a Geiger counter, sensors to monitor the temperature of the spacecraft, and two payloads – an acoustic sensor and an erosion wire grid – to detect micrometeoroid impacts.

To relay the results of its experiments to the ground, Explorer 1 carried two transmitters consisting of a 60-milliwatt amplitude-modulated (AM) transmitter and a 10-milliwatt phase-modulated (PM) transponder.

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The radiation belts would become known as the Van Allen Belts, after Dr. James A. Van Allen of the University of Iowa, who was the mission’s principal investigator.

Explorer 1 was battery-powered and functioned successfully for nearly four months, ceasing operations once its batteries were depleted.

Explorer 1 was the first satellite of what would become NASA’s Explorer programme. The name Explorer has continued to be used for NASA’s small scientific research missions, with the most recent satellite in the series – IRIS, or Explorer 94 – launched in June 2013.

The next mission in the Explorer series is ICON (Ionospheric Connection Explorer), due for launch at the end of February.

Sixty years on, state of the US space program is strong:

Public support and perception of the US space program has always been a prominent factor in US space operations since their commencement in the 1950s. As with any long-running program, those perceptions and support have ridden a wave of enthusiasm and highs as well as troughs of depression and concern.

The public nature of the US space program has – above all – provided an immense source of pride, elation, and joy for not just its successes and invaluable scientific exploration efforts, but also for its recovery from failure.

From early failures that eventually led to the first US astronauts reaching space, these recoveries from failures and missteps have been one of the cornerstones of the US space program’s interaction with the public – with the rousing success of Apollo 11 following the tragedy of Apollo 1, with the return to flight of the Shuttle and creation of what would become the International Space Station following the Challenger disaster, and the decision to foster the addition of more commercial companies to the launch community following the Columbia accident.

While NASA is currently transitioning its ability to launch astronauts from the United States from government-owned rockets to commercially built and contracted rockets and capsules, both of the companies with which NASA has those contracts – SpaceX and Boeing – are slated to debut their new crew capsules in uncrewed demo flights this year.

For SpaceX, this demonstration is set to continue a highly successful string of impressive records the company has achieved over the last year. In the one year period from 14 January 2017 to 13 January 2018, SpaceX accomplished an impressive 19 successful flights of their Falcon 9 flagship rocket, returning many of those boosters to successful landings on either ASDS drone ships in the Atlantic or Pacific oceans or back to Landing Zone 1 at the Cape Canaveral Air Force Station.

For SpaceX, 2018 holds the potential to be just as historic and meaningful as last year. Overall, the company has 30 missions of its Falcon family of rockets planned this year, including the highly anticipated debut next week of Falcon Heavy, the commencement of commercial crew launch capabilities, launching NASA’s Transiting Exoplanet Survey Satellite (TESS) mission, as well as numerous missions for the US government, international companies/organizations/governments, and US-based companies.

Blue Origin is nearing completion of its manufacturing facility on Merritt Island for its upcoming heavy-lift New Glenn rocket while continuing to make extremely positive strides in the arena of suborbital, commercial spaceflight for paying customers.

Meanwhile, the agency’s fleet of Mars explorers, both in orbit and on the surface, continue to record invaluable data about the red planet that will greatly aid humanity’s exploration and colonization efforts of our celestial neighbor.

A flight-proven Falcon 9 with GovSat1/SES-16 on SLC-40 ahead of launch. Credit: Chris Gebhardt for NASASpaceflight

In short, the state of the US space program is strong, perhaps stronger than ever as numerous commercial and government agencies push our boundaries of knowledge, exploration, and technology for the betterment of the future.